Here is an assortment of playful Japanese postcards from the late 19th and early 20th centuries, found in a recent book by collector Hiroki Hayashi entitled "Antique Cute Post Cards in Japan" (Nippon no kawaii ehagaki).

Betty Boop (Yamaguchi Seikyokudo Co., Ltd. - c. 1930s)

Betty Boop (1937)

Betty Boop, Mickey and Minnie (1936)

Mickey (c. 1920s-40s)

Kewpie Mayonnaise ad (1932)

Kewpie (c. 1920s-40s)

Kewpie (1933/1935)

Kewpie (c. 1920s-40s)

Kewpie (Shoseido - 1919)

Kewpie (Shoseido - 1919)

Kewpie (c. 1920s-40s)

Kewpie (c. 1920s-40s)

"Bring it on" (Propaganda card by Kiyoshi - 1940)

"I've got your back" (Military Mail greeting card for troops - 1940)

Dancing skeletons (c. 1890s-1900s)

Yoshikawa Roppa (Hibiya Yurakuza Theater - 1940)

New Year's Card (1911)

Muscles and blood vessels (1920)

Standing in flames (Shokichiro Yamaguchi - c. 1920s)

Postcard commemorating Children's Expo (Dobunkan - 1906)

One in a series of naughty joke cards (Toyo Postcard Association - c. 1900s-10s)

Melody

I agree with @Con Artist Trickster: I never knew that Japan even had Betty Boop, much less that she was a successful import there. :/

I guess maybe she could have been a design influence on Rock Lee after all, then. :? There used to be more of those back when Naruto was popular, but I guess they're no longer online; but back when Naruto was the big thing, a few of the fans were saying that Betty Boop was his long-lost-mom/design inspiration, and I always thought it was impossible, since I didn't think that Betty Boop was ever marketed to Japan...